信息安全系统设计基础第五次实验报告

北京电子科技学院（BESTI）

实 验 报 告

课程：信息安全系统设计基础 班级： 1353

姓名：（按贡献大小排名）朱锂 陈都

学号：（按贡献大小排名）20135319 20135328

成绩： 指导教师： 娄嘉鹏 实验日期：11.10

实验密级： 预习程度： 实验时间：15:30—18：00

仪器组次： 必修/选修：必修 实验序号：5

实验名称：信息安全系统设计基础EXP5—简单嵌入式WEB服务器实验

实验目的与要求：

1 看懂代码，在宿主机和实验箱中实现。

2 查找C语言密码算法库，在通信中使用密码算法

实验内容与步骤：

1 进入/arm2410cl/exp/basic/07_httpd 目录，使用 vi 编辑器或其他编辑器阅读理解源代码

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <sys/stat.h>
#include <dirent.h>
#include <signal.h>
#include <unistd.h>
#include <ctype.h>
#include "pthread.h"

#define DEBUG

int KEY_QUIT=0;
int TIMEOUT=30;

#ifndef O_BINARY
#define O_BINARY 0
#endif

char referrer[128];
int content_length;

#define SERVER_PORT 80

int PrintHeader(FILE *f, int content_type)
//发送http协议数据头
//参数一表示客户连接的文件流指针
//参数二表示信息类型
{
alarm(TIMEOUT);
fprintf(f,"HTTP/1.0 200 OK\n");
switch (content_type)
{
case 't':
fprintf(f,"Content-type: text/plain\n");
break;
case 'g':
fprintf(f,"Content-type: image/gif\n");
break;
case 'j':
fprintf(f,"Content-type: image/jpeg\n");
break;
case 'h':
fprintf(f,"Content-type: text/html\n");
break;
}
fprintf(f,"Server: uClinux-httpd 0.2.2\n");
fprintf(f,"Expires: 0\n");
fprintf(f,"\n");
alarm(0);
return(0);
}

int DoJpeg(FILE *f, char *name)
//发送jpeg
//参数一文件数据信息
//参数二文件名
{
char *buf;
FILE * infile;
int count;

if (!(infile = fopen(name, "r"))) {
alarm(TIMEOUT);
fprintf(stderr, "Unable to open JPEG file %s, %d\n", name, errno);
fflush(f);
alarm(0);
return -1;
}

PrintHeader(f,'j');

copy(infile,f); /* prints the page */

alarm(TIMEOUT);
fclose(infile);
alarm(0);

return 0;
}

int DoGif(FILE *f, char *name)
//发送gif文件
//参数一文件数据信息
//参数二文件名
{
char *buf;
FILE * infile;
int count;

if (!(infile = fopen(name, "r"))) {
alarm(TIMEOUT);
fprintf(stderr, "Unable to open GIF file %s, %d\n", name, errno);
fflush(f);
alarm(0);
return -1;
}

PrintHeader(f,'g');

copy(infile,f); /* prints the page */

alarm(TIMEOUT);
fclose(infile);
alarm(0);

return 0;
}

int DoDir(FILE *f, char *name)
//发送当前目录列表信息
//参数一文件流指针用于写入目录文件信息数据
//参数二客户请求的目录信息
{
char *buf;
DIR * dir;
struct dirent * dirent;

if ((dir = opendir(name))== 0) {
fprintf(stderr, "Unable to open directory %s, %d\n", name, errno);
fflush(f);
return -1;
}

PrintHeader(f,'h');

alarm(TIMEOUT);
fprintf(f, "<H1>Index of %s</H1>\n\n",name);
alarm(0);

if (name[strlen(name)-1] != '/') {
strcat(name, "/");
}

while(dirent = readdir(dir)) {
alarm(TIMEOUT);

fprintf(f, "<p><a href=\"/%s%s\">%s</a></p>\n", name, dirent->d_name, dirent->d_name);
alarm(0);
}

closedir(dir);
return 0;
}

int DoHTML(FILE *f, char *name)
//发送 HTML 文件内容
//参数一写入文件数据信息
//参数二客户请求的文件名
{
char *buf;
FILE *infile;
int count;
char * dir = 0;

if (!(infile = fopen(name,"r"))) {
alarm(TIMEOUT);
fprintf(stderr, "Unable to open HTML file %s, %d\n", name, errno);
fflush(f);
alarm(0);
return -1;
}

PrintHeader(f,'h');
copy(infile,f); /* prints the page */

alarm(TIMEOUT);
fclose(infile);
alarm(0);

return 0;
}

int DoText(FILE *f, char *name)
//发送纯文本文件内容
//参数一写入文件信息数据
//参数二写入文件名
{
char *buf;
FILE *infile;
int count;

if (!(infile = fopen(name,"r"))) {
alarm(TIMEOUT);
fprintf(stderr, "Unable to open text file %s, %d\n", name, errno);
fflush(f);
alarm(0);
return -1;
}

PrintHeader(f,'t');
copy(infile,f); /* prints the page */

alarm(TIMEOUT);
fclose(infile);
alarm(0);

return 0;
}

int ParseReq(FILE *f, char *r)
//解析客户请求，参数一表示客户连接的文件流指针
//参数二，待解析的字符串
{
char *bp;
struct stat stbuf;
char * arg;
char * c;
int e;
int raw;

#ifdef DEBUG
printf("req is '%s'\n", r);
#endif

while(*(++r) != ' ');  /*skip non-white space*/
while(isspace(*r))
r++;

while (*r == '/')
r++;
bp = r;

while(*r && (*(r) != ' ') && (*(r) != '?'))
r++;

#ifdef DEBUG
printf("bp='%s' %x, r='%s' \n", bp, *bp,r);
#endif

if (*r == '?')
{
char * e;
*r = 0;
arg = r+1;
if (e = strchr(arg,' '))
{
*e = '\0';
}
} else
{
arg = 0;
*r = 0;
}

c = bp;

if (c[0] == 0x20){
c[0]='.';
c[1]='\0';
}
if(c[0] == '\0') strcat(c,".");

if (c && !stat(c, &stbuf))
{
if (S_ISDIR(stbuf.st_mode))
{
char * end = c + strlen(c);
strcat(c, "/index.html");
if (!stat(c, &stbuf))
{
DoHTML(f, c);
}
else
{
*end = '\0';
DoDir(f,c);
}
}
else if (!strcmp(r - 4, ".gif"))
DoGif(f,c);
else if (!strcmp(r - 4, ".jpg") || !strcmp(r - 5, ".jpeg"))
DoJpeg(f,c);
else if (!strcmp(r - 4, ".htm") || !strcmp(r - 5, ".html"))
DoHTML(f,c);
else
DoText(f,c);
}
else{
PrintHeader(f,'h');
alarm(TIMEOUT);
fprintf(f, "<html><head><title>404 File Not Found</title></head>\n");
fprintf(f, "<body>The requested URL was not found on this server</body></html>\n");
alarm(0);
}
return 0;
}

void sigalrm(int signo)
{
exit(0);
}

int HandleConnect(int fd)//控制连接
{
FILE *f;

char buf[160];
char buf1[160];

f = fdopen(fd,"a+");
if (!f) {
fprintf(stderr, "httpd: Unable to open httpd input fd, error %d\n", errno);
alarm(TIMEOUT);
close(fd);
alarm(0);
return 0;
}
setbuf(f, 0);

alarm(TIMEOUT);

if (!fgets(buf, 150, f)) {
fprintf(stderr, "httpd: Error reading connection, error %d\n", errno);
fclose(f);
alarm(0);
return 0;
}
#ifdef DEBUG
printf("buf = '%s'\n", buf);
#endif

alarm(0);

referrer[0] = '\0';
content_length = -1;

alarm(TIMEOUT);

while (fgets(buf1, 150, f) && (strlen(buf1) > 2)) {
alarm(TIMEOUT);
#ifdef DEBUG
printf("Got buf1 '%s'\n", buf1);
#endif
if (!strncasecmp(buf1, "Referer:", 8)) {
char * c = buf1+8;
while (isspace(*c))
c++;
strcpy(referrer, c);
}
else if (!strncasecmp(buf1, "Referrer:", 9)) {
char * c = buf1+9;
while (isspace(*c))
c++;
strcpy(referrer, c);
}
else if (!strncasecmp(buf1, "Content-length:", 15)) {
content_length = atoi(buf1+15);
}
}
alarm(0);

if (ferror(f)) {
fprintf(stderr, "http: Error continuing reading connection, error %d\n", errno);
fclose(f);
return 0;
}

ParseReq(f, buf);

alarm(TIMEOUT);
fflush(f);
fclose(f);
alarm(0);
return 1;
}

void* key(void* data)
{
int c;
for(;;){
c=getchar();
if(c == 'q' || c == 'Q'){
KEY_QUIT=1;
exit(10);
break;
}
}

}

int main(int argc, char *argv[])
{
int fd, s;
int len;
volatile int true = 1;
struct sockaddr_in ec;
struct sockaddr_in server_sockaddr;

pthread_t th_key;
void * retval;

signal(SIGCHLD, SIG_IGN);
signal(SIGPIPE, SIG_IGN);
signal(SIGALRM, sigalrm);

chroot(HTTPD_DOCUMENT_ROOT);
printf("starting httpd...\n");
printf("press q to quit.\n");
//  chdir("/");

if (argc > 1 && !strcmp(argv[1], "-i")) {
/* I'm running from inetd, handle the request on stdin */
fclose(stderr);
HandleConnect(0);
exit(0);
}

if((s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1) {
perror("Unable to obtain network");
exit(1);
}

if((setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (void *)&true,
sizeof(true))) == -1) {
perror("setsockopt failed");
exit(1);
}

server_sockaddr.sin_family = AF_INET;
server_sockaddr.sin_port = htons(SERVER_PORT);
server_sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);

if(bind(s, (struct sockaddr *)&server_sockaddr,
sizeof(server_sockaddr)) == -1)  {
perror("Unable to bind socket");
exit(1);
}

if(listen(s, 8*3) == -1) { /* Arbitrary, 8 files/page, 3 clients */
perror("Unable to listen");
exit(4);
}

pthread_create(&th_key, NULL, key, 0);
/* Wait until producer and consumer finish. */
printf("wait for connection.\n");
while (1) {

len = sizeof(ec);
if((fd = accept(s, (void *)&ec, &len)) == -1) {
exit(5);
close(s);
}
HandleConnect(fd);

}
pthread_join(th_key, &retval);
}

2 编译应用程序 运行 make 产生可执行文件 httpd

[root@zxt /]# cd /arm2410cl/exp/basic/07_httpd/
[root@zxt 07_httpd]# make
armv4l-unknown-linux-gcc -DHTTPD_DOCUMENT_ROOT=\"/mnt/yaffs\" -c -o httpd.o httpd.c
armv4l-unknown-linux-gcc -DHTTPD_DOCUMENT_ROOT=\"/mnt/yaffs\" -c -o copy.c
armv4l-unknown-linux-gcc -o ../bin/httpd httpd.o copy.o -lpthread
armv4l-unknown-linux-gcc -o httpd httpd.o copy.o -lpthread
[root@zxt 07_httpd]# ls
copy.c doc httpd httpd.o Makefile
copy.o Google httpd.c index.html Makefile.bak

3 下载调试 使用 NFS 服务方式将 HTTPD 下载到开发板上，并拷贝测试用的网

页进行调试，本例中用的是 index 测试网页。

[/mnt/yaffs] mount -t nfs -o nolock 192.168.0.56:/arm2410cl /host
[/mnt/yaffs]cd /host/exp/basic/07_httpd/
[/host/exp/basic/07_httpd]./httpd
starting httpd...
press q to quit.
wait for connection.

实验体会：

通过这次实验，我们又知道了一种嵌入式系统的应用方法，由于操作的层面比通常开发web应用所在层次更加底层，这对于我们对于web应用的深入理解也是一种加强。